84 



ANATOMY FOR NURSES 



[Chap. VI 



Fig. 62. — Diameters and I.andmahks of the Fcetal Skull. Posterior 

 surface. (Edgar.) 



AMPHIARTHROSES, OR SLIGHTLY MOVABLE JOINTS 



The above terms apply to joints that permit of slight movement 

 and include two varieties: (1) symphysis, and (2) syndesmosis. 



Symphysis. — In this form of articulation the bony surfaces are 

 joined together by broad, flattened disks of fibro-cartilage, as in 



the articulations between the bodies of 

 the vertebrse. These intervertebral disks 

 being compressible and extensile, the 

 spine can be moved to a limited extent 

 in every direction. In the pelvis the 

 articulation between the two pubic bones 

 (symphysis pubis), and between the sac- 

 rum and ilia (sacro-iliac articulation), 

 are slightly movable. The pubic bones 

 are united by a disk of fibro-cartilage and by ligaments. In the 

 sacro-iliac articulation the sacrum is united more closely to the 



Fio. 63. — A Slightly 

 Movable Joint, a, b, disk 

 of fibro-cartilage ; c, articular 

 cartilage ; d, bone. 



